Giant reversible rotating cryomagnetocaloric effect in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="normal">KEr</mml:mi><mml:mo>(</mml:mo><mml:msub><mml:mtext>MoO</mml:mtext><mml:mn>4</mml:mn></mml:msub><mml:mo>)</mml:mo><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>induced by a crystal-field anisotropy

Tkáč, V.; Orendáčová, A.; Čižmár, E.; Orendáč, M.; Feher, A.; Anders, A. G.

doi:10.1103/physrevb.92.024406

Cited by 53 publications

(20 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the use of anisotropic magnetocaloric materials can provide an opportunity for reducing this operation time down to the order of seconds. This can be attained by rotating well‐oriented single crystals of an anisotropic magnetocaloric material in a constant applied magnetic field, as experimentally investigated for HoMn 2 O 5 and KEr(MoO 4 ) 2 . In fact, the MCE of anisotropic magnetic materials varies depending on the orientation of B .…”

Section: Figurementioning

confidence: 96%

Rotating Magnetocaloric Effect in an Anisotropic Molecular Dimer

2016

View full text Add to dashboard Cite

In contrast to the mainstream research on molecular refrigerants that seeks magnetically isotropic molecules, we show that the magnetic anisotropy of dysprosium acetate tetrahydrate, [{Dy(OAc)3(H2O)2}2]⋅4 H2O (1), can be efficiently used for cooling below liquid‐helium temperature. This is attained by rotating aligned single‐crystal samples in a constant applied magnetic field. The envisioned advantages are fast cooling cycles and potentially compact refrigerators.

show abstract

Section: Figurementioning

confidence: 96%

Rotating Magnetocaloric Effect in an Anisotropic Molecular Dimer

2016

View full text Add to dashboard Cite

show abstract

“…Most of the research concerning rotating magnetocaloric effect deals with inorganic materials [59][60][61]63,64,[66][67][68] and there are only few examples related to molecular magnets [69]. In our research we have focused on two-dimensional molecular compounds which reveal magnetic anisotropy and transition to long-range ordered phase.…”

Section: Rotating Magnetocaloric Effect In Anisotropic Two-dimensionamentioning

confidence: 99%

Multifunctional Molecular Magnets: Magnetocaloric Effect in Octacyanometallates

et al. 2018

View full text Add to dashboard Cite

Octacyanometallate-based compounds displaying a rich pallet of interesting physical and chemical properties, are key materials in the field of molecular magnetism. The [M(CN)8]n− complexes, (M = WV, MoV, NbIV), are universal building blocks as they lead to various spatial structures, depending on the surrounding ligands and the choice of the metal ion. One of the functionalities of the octacyanometallate-based coordination polymers or clusters is the magnetocaloric effect (MCE), consisting in a change of the material temperature upon the application of a magnetic field. In this review, we focus on different approaches to MCE investigation. We present examples of magnetic entropy change ΔSm and adiabatic temperature change ΔTad, determined using calorimetric measurements supplemented with the algebraic extrapolation of the data down to 0 K. At the field change of 5T, the compound built of high spin clusters Ni9[W(CN)8]6 showed a maximum value of −ΔSm equal to 18.38 J·K−1 mol−1 at 4.3 K, while the corresponding maximum ΔTad = 4.6 K was attained at 2.2 K. These values revealed that this molecular material may be treated as a possible candidate for cryogenic magnetic cooling. Values obtained for ferrimagnetic polymers at temperatures close to their magnetic ordering temperatures, Tc, were lower, i.e., −ΔSm = 6.83 J·K−1 mol−1 (ΔTad = 1.42 K) and −ΔSm = 4.9 J·K−1 mol−1 (ΔTad = 2 K) for {[MnII(pyrazole)4]2[NbIV(CN)8]·4H2O}n and{[FeII(pyrazole)4]2[NbIV(CN)8]·4H2O}n, respectively. MCE results have been obtained also for other -[Nb(CN)8]-based manganese polymers, showing significant Tc dependence on pressure or the remarkable magnetic sponge behaviour. Using the data obtained for compounds with different Tc, due to dissimilar ligands or other phase of the material, the ΔSm ~ Tc−2/3 relation stemming from the molecular field theory was confirmed. The characteristic index n in the ΔSm ~ ΔHn dependence, and the critical exponents, related to n, were determined, pointing to the 3D Heisenberg model as the most adequate for the description of these particular compounds. At last, results of the rotating magnetocaloric effect (RMCE), which is a new technique efficient in the case of layered magnetic systems, are presented. Data have been obtained and discussed for single crystals of two 2D molecular magnets: ferrimagnetic {MnII(R-mpm)2]2[NbIV(CN)8]}∙4H2O (mpm = α-methyl-2-pyridinemethanol) and a strongly anisotropic (tetren)Cu4[W(CN)8]4 bilayered magnet showing the topological Berezinskii-Kosterlitz-Thouless transition.

show abstract

“…The first coordination sphere of Er 3+ consists of eight oxygen atoms forming a slightly distorted square antiprism. The ground state of a free Er 3+ is 4 I 15/2 multiplet, which is split into 8 Kramers doublets with the energies E 1 = 22, (893) [4]. Interplay of crystal field and dipolar interactions results in the formation of a two-dimensional array of the Ising ferromagnetic chains below 2 K. The antiferromagnetic interchain coupling leads to the phase transition to magnetic long-range order at 0.9 K [8].…”

Section: Methodsmentioning

confidence: 99%

“…A huge anisotropy of MCE was observed in the ab plane with -∆S r , max = 10 and 13 J/(kg K) achieved by a simple rotating of the single crystal within the ab plane in the constant magnetic field 2 and 5 T, respectively [4]. Thus, KEr(MoO 4 ) 2 may serve as a promising candidate for the implementation of a compact rotary magnetic cryorefrigerator.…”

Section: Introductionmentioning

confidence: 99%

Magnetic-Field Induced Slow Relaxation in the Ising-Like Quasi-One-Dimensional Ferromagnet KEr(MoO_4)_2

et al. 2017

Self Cite

View full text Add to dashboard Cite

We present the study of spin dynamics of KEr(MoO4)2 in the magnetic field applied along the hard axis c. The temperature dependence of AC susceptibility in zero magnetic field studied at frequencies f = 10, 100, and 1000 Hz indicated the absence of relaxation in the temperature range from 2 to 20 K. Application of magnetic field induced a slow magnetic relaxation, which was investigated in detail in the field 0.5 T. The highest intensity of the relaxation process, reflected by the values of imaginary susceptibility was observed at 2 K. With increasing temperature, the relaxation process is weaker and vanishes completely above 3.5 K. Corresponding Cole-Cole diagrams were constructed and analyzed within a single relaxation process which can be associated with a direct relaxation process with a bottleneck effect, τ ≈ 1/T b , and b = 1.4. The slow relaxation at 2 K intensifies with increasing magnetic field at least up to 1 T.

show abstract

Giant reversible rotating cryomagnetocaloric effect inKEr(MoO4)2induced by a crystal-field anisotropy

Cited by 53 publications

References 24 publications

Rotating Magnetocaloric Effect in an Anisotropic Molecular Dimer

Rotating Magnetocaloric Effect in an Anisotropic Molecular Dimer

Multifunctional Molecular Magnets: Magnetocaloric Effect in Octacyanometallates

Magnetic-Field Induced Slow Relaxation in the Ising-Like Quasi-One-Dimensional Ferromagnet KEr(MoO_4)_2

Contact Info

Product

Resources

About